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THE MCAT-ORGO

QuestionAnswer
What shape has the lowest heat of conbustion and lowest potential energy? cyclohexane
Can meso cpds have chiral centers? YES --> although overall, they are achiral and optically inactive
Enantiomers have the same / different chemical properties. same
Diastereomers have the same / different chemical properties. different
How to calculate number of different stereoisomers? 2^(*chiral centers) - # meso
Conformational isomers same molecular formula, same connectivity, same stereochem, but rotate about a single bond
Rate conformational isomers based on decreasing stability. Anti, gauche, eclipsed
Rank chair, boat, twist boat based on increasing stability. boat, twist boat, chair
Normal light has EM fields in all directions but polarized light has EM fields in _____ direction one
Chiral molecules will rotate polarized light either to the _____ or _______. -left (-) or (l) -right (+) or (d)
According to rules for assigning priority, what factor dominates most? MOLECULAR WEIGHT --> then look at more bonds to higher priority
Do racemic mix rotate polarized light? Are they optically active? NO --> optically inactive
How to separate enantiomers through diastereomers? -convert enantiomers to diastereomers -separate diastereomers -convert diastereomers back to enantiomers
How to separate enantiomers by biological means? enzymes are highly specific and can differentiate between enantiomers
In nature, all proteins are made up of ___ amino acids L
How many valence electrons / number of bonds for phosphorous? -5 -3 or 5
How many valence electrons / number of bonds for sulfur? -6 -2 or 6
How many valence electrons / number of bonds for silicon? -4 -4
VSEPR: 3 bonds, one unbonded electron pair trigonal pyramidal
VSEPR: 2 bonds, 2 unbonded electron pair bent
VSEPR: 4 bonds trigonal bipyramidl
VSEPR: 4 bonds, one unbonded electron pair seesaw
VSEPR: 3 bonds, 2 unbonded electron pair T-shaped
VSEPR: 2 bonds, 3 unbonded electron pair linear
VSEPR: 6 bonds octahedral
VSEPR: 5 bonds, one unbonded electron pair square pyramidal
VSEPR: 4 bonds, 2 unbonded electron pair square planar
VSEPR: 3 bonds, 3 unbonded electron pair T-shaped
VSEPR: 2 bonds, 4 unbonded electron pair linear
Resonance: single C-C bonds are shorter and ? stronger
Resonance: double C-C bonds are longer and ? weaker
What are meso cpds? made up of 2 halves that are mirror images
Why is chair most stable? eliminates 3 types of strain
Why are boats unstable? all atoms are eclipsed
Index of hydrogen deficiency # = (2n+2) + N - H - X / 2
What is bond energy? energy required to break a bond
Why is a pi bond less stable/weaker than a sigma bond? pi bonds are in higher energy level , less stable, more reactive
What is Huckel's Rule 4n + 2pi
What is measured in IR-Spectroscopy? bond vibrations
What is on x-axis / y-axis of IR spectroscopy? -x-axis: frequency of vibration -y-axis transmittance
Where transmittance dips down in IR, what does it indicate? region of absorbance
IR: What are broad peaks due to? hydrogen bonding
IR: Below 1300 cm is called ____ fingerprint region - unique for each cpd
IR: 1700 cm = carbonyl group
IR: 3300 cm can be ______, ______, or _____. -OH - broadest -NH - slightly sharper -alkyne CH - very sharp
IR: Anything around 2000 cm and below does not involve _______. hydrogen (C=O, C=C, C-C, C-O)
Indicators: Red is ______ and blue is _______ and green is _____. acidic / basic / neutral
H-indicator vs. Indicator -At low pH, H-indicator and color will predominate -At high pH, indicator and color will predominate
valence vs. oxidation number -valence = number of electrons in outermost shell -oxidation = number of valence electrons gained or lost
Formula for ammonia vs. ammonium? NH3 vs. NH4+
structural isomers same molecular formula, different connectivity
positional isomers a type of structural isomers that have the same functional groups but are positioned differently
constitional isomers a type of structural isomers that have same molecular formula but completely different functional groups
What are stereoisomers? diastereomers, enantiomers, cis / trans
D/L vs. d/l -D/L = absolute configuration -d/l = relative configuration (how it rotates light)
Why are enantiomers difficult to separate? similar physical properties
What creates a net spin in NMR? odd number of protons
What is resonance frequency? frequency of radio wave that is needed for proton to flip in spin and spin opposite to direction of external B-field
The more conjugated double bonds, the longer / shorter the wavelengths of absorbed radiation? longer
Conjugated systems decrease / increase the energy of EM radiation that is absorbed? decrease
What does UV spectroscopy measure? detects conjugated double bonds by comparing intensities of 2 beams of light
What is a conjugated system? double bond separated with single bond
Each additional conjugated double bond increases the wavelength absorbed by ___ nm 30-40 nm
UV spectroscopy: UV photons are able to displace electrons to _____ and energy is absorbed. LUMO
LUMO vs. HOMO lowest unoccupied molecular orbital vs. highest occupied molecular orbital
What is the transition observed for UV absorption for hyperconjugation? bonding and nonbonding orbitals --> anti-bonding orbitals
Carrots with beta-carotene absorb _____ light and emit _____ light. blue / green orange
If a cpd has eight or more hyperconjugated bonds, absorbance moves into? visible spectrum
mass spectrometry: parent peak most rightfield peak that depicts ion without fragmentation -highest m/z ratio
mass spectrometry: base peak most abundant species (tallest peak)
mass spectrometry: peaks clustered really close to each other isotopes
What is mass spectrometry useful for? measuring molecular weight of a molecule (m/z) ratio
mass spectrometry: m /z ratio mass to charge ratio
How does NMR work? EM radiation of certain frequency is shown on nuclei that can flip the spin of the nuclei
What is varied in NMR? magnetic field strength -frequency is kept constant
Aldehydes have ____ ppm in NMR around 9
What does NMR depict? neighboring hydrogens
When things are shielded, what happens? rightward shift --> B-field is increasing
When things aren't shielded, what happens? leftward shift --> B-field is decreasing
NMR: What do EWG do? lower shielding and decrease B-field strength at which resonance takes place --> left shift
NMR: What do EDG do? -increase shielding and increase field strength required for resonance --> right shift
What is extraction based upon? like dissolves like
What are the steps for extraction? -add strong acid - protonates bases - remove bases -add weak base - deP only strong acids - remove strong acids -add strong base - deP everything else - remove weak acids
fractional distillation used to separate liquids with smaller diff in BP --> run vapor through glass beads so cpd with higher BP will condense
vacuum distillation lowers BP for both so less decomposition / volatility
What problems do azeotropes create in distillation? azeotrope can have higher / lower BP than either of the 2 pure substances
Gas-liquid chromatography - what is mobile phase and what is stationary phase -mobile: gas phase -stationary: liquid coating the inside walls of column
Paper chromatography: what polarity is paper / solvent -paper = polar -solvent = nonpolar
Calculate Rf factor distance traveled by pigment / distance traveled by solvent
What is the basic idea behind chromatography? cpds in mixture that have greater affinity for stationary phase move more slowly
column chromatography solution is dripped down a column with beads containing the stationary phase --> polar cpds travel slower
Crystallization principle -pure substances form crystals easier than impure substances -impurities should remain dissolved in solvent even when cpd crystallizes out --> iceberg in salt water
What type of solvent is good for recrystalization? -solvent where cpd dissolves only at warm temp, not cold temp -impurities are highly soluble
Thin-layer chromatography vs. paper chromatography TLC uses coated glass or plastic plate and results are visualized via an iodine vapor chamber
What is the boiling point of heptane? 100C --> same as water
What does alkane combustion produce? carbon dioxide and water
Alkane + halogen + free radical initiator (UV light or peroxides) = alkyl halide
Substitution for halogen of an alkane will occur at more/less substituted carbon more
What inhibits free radical mechanism? antioxidants (eat up free radicals to inhibit rxn)
What does the free radical mechanism depend on? presence of free radicals
What has the highest ring strain? lowest ring strain? -cyclopropane (both Baeyer and torsional strain) -cyclohexane (neither)
After cyclohexane, what has the next lowest ring strain? any ring with greater or equal to 14 carbons
What creates ring strain? Baeyer Strain (deviation from ideal sp3-109.5) Torsional Strain-molecule having eclipsed instead of staggered
Do bicyclic molecules have more or less ring strain than monocyclic molecules? MORE
How do aldehydic protons appear in H-NMR? singlet
How to extract amines? -add HCl -->amines are protonated to create + charge and make it soluble
How does cis translate to chair drawing? How does trans? -one equatorial and other axial -both equatorial / both axial
On the same dash/wedge, are 1,3 / 1,4 / 1,2 cis or trans? -1,3 = trans -1,4 / 1,2 = cis
On different dashes / wedges, are 1,3 / 1,4 / 1,2 cis or trans? -1,3 = cis -1,4 / 1,2 = trans
What is fractional distillation? distillation based on different BP
Why do tertiary alcohols react faster with HCl? carbocation stability
How to make the CH3MgBr Grignard reagent? Mix CH3Br + Mg in diethyl ehter
Saponification hydrolysis of ester in f.a. with NaOH
What is a f.a. made of? alcohol and COOH
Where is most of the electron density in a sigma bond? between the nuclei
How many bonds can boron form? 3
More highly substituted carbons have stronger or weaker bonds? weaker
Which atoms normally hydrogen bond? fluorine, oxygen, nitrogen
What is a vinylic carbon? C = C
When does electron withdrawing occur? a more electronegative atom draws away electorn density
A good nucleophile has high / low electron density? high electron density
Why do EWGs make nucleophiles worse? draw away electron density and nu becomes worse electron donor
More electronegative atoms withdraw more or less electron density and make for a poorer nucleophile? more electron density
Shortcut to remember relative electronegativity? FONClBrISCH
Steric repulsion theory Electrons will repel electrons and will decrease bond angles
Can a proton be involved with resonance? NO
What creates a strong acid in terms of its conjugate base? a stable conjugate base (such as aromatic base) = strong acid
lewis acid / base electron acceptor / electron donor
bronsted lowry acid / base H donor / H acceptor
What is 5-10-15-20 rule for organic acids? -pKa for COOH = 5 -phenol = 10 -alcohol = 15 -proton alpha to carbonyl = 20
In COOH, the carbonyl oxygen is more likely to get protonated than the hydroxyl oxygen which means? the carbonyl oxygen is more basic than the alcohol oxygen
Does a partial negative charge increase or decrease basicity? increase
Bases like to get _____ acids like to get _______. protonated / deprotonated
Does a larger/smaller atom create a stronger acid? Does this apply to periods or groups? larger / groups
Does a more / less eN atom create a stronger? Does this apply to periods or group? Why is this so? more eN / periods / stabilize high electron density and makes it easier to break bond
What hybridization creates a strong acid? Why? sp / electrons are held closer to the nucleus so bond can be cleaved easier
An adjacent atom making a pi bond is EWG / EDG? Lone pair atom is EWG / EDG? EWG / EDG
Where do EDG increase electron density in aromatic ring? ortho and para --> O / P more nu so reacts with electrophiles at O/P
Where do EWG decrease electron density in aromatic ring ortho and para --> O / P less nu. so reacts with electrophiles at meta
What do atomic size, eN, and hybridization deal with? bond directly to acidic proton
What does inductive effect refer to? EWG and EDG
In terms of lone pair, what creates a basic atom? when lone pair is least shared
Do Van der Waals forces exist between all compounds? YES --> forces are roughly equal too
What creates the strongest H-bond? hydrogen on fluorine and lone pair from nitrogen
To have hydrogen bonding, where must the hydrogen be located? on an F, O, N
To create a rigid phospholipid membrane, what type of fatty acid should be used? long, saturated fatty acids --> maximize interactions between liid chains
Why is lard solid at room temperature while veggie oil is liquid? lard is saturated structure which means more flexible which means individual molecules interact with each other strongly
Do unsaturated fats increase / decrease membrane fluidity? increase
Do unsaturated or saturated fats have higher melting temperature? saturated fats
solubility vs. miscibility -ability of solid to dissolve into solution -ability of liquid to mix into another liquid
What are the types of IMF in polar, protic solvents? H-bonds, dipole-dipole, van der Waals
What are the types of IMF in polar, aprotic solvents? dipole-dipole and van der Waals
What are the types of IMF in nonpolar, aprotic solvents? van der Waals
What creates the best micelle? ionic head and long carbon chain
Where do sigma bonds share electron density vs. pi bonds? -between nuclei -in plane above and below nuclei
To create a bonding orbital, add/subtract nuclei? antibonding orbital? add / subtract
Is a bonding orbital less or more stable than antibonding orbitals? more stable
Are sigma bonds more or less stable than pi bonds? more stable
How to tell if 2 isomers are structural isomers? have different IUPAC names
Is it possible to rotate around a double bond? NO --> p-orbitals would no longer be coplanar breaking the pi bond
Do alkenes have lower or greater entropy than alkanes? lower entropy
On an energy diagram for conformational isomers, if greatest substituents repel each other, then which orientation is most stable with lowest energy? anti
On energy diagram for conformational isomers, if greatest substituents attract each other, which orientation is most stable with lowest energy? gauche (like vicinol diol)
On a newman projection, the substituents behind the plane are on the right or left? substituents in front of the plane? right / left
Which ring structures are most stable / least stable? -5/6 membered rings -3/4 membered ring
In a chair, cis refers to? up / up or down down
In a chair, what does trans refer to? up / down
What do wedges translate to on chair diagram? up
What do dashes translate to on chair diagram? down
What is the formula for the PE that is associated with H-NMR spectroscopy? PE = 1/2 kx^2
What does no broad peaks above 2500 cm-1 indicate? no OH bond
IR: What do peaks in the 1300-1400 range indicate? C-C bonds
In organic chemistry, what must a compound have in order to be UV-visibly active? pi bond
For UV spectroscopy, as conjugation increases, does energy gap between pi and pi* decrease or increase? How does this affect wavelength of max. absorbance decreases / increases
When more conjugation is added, where does the absorbance shift into? visible range
What does color result from? excessive conjugation
What do infrared photons affect that is different from UV and visible photons? -infrared affects vibrational energies -UV and visible affect electronic energy levels
For H-NMR, where is upfield and does that mean low or high B-field strength? right --> high B-field strength
For H-NMR, where is downfield and does that mean low or high B-field strength? left --> low B-field strength
EWG lower shielding and cause a right/left shift in H-NMR? decrease the B-field strength at which resonance takes place -left
EDG raise shielding and cause a right/left shift in H-NMR? increase B-field strength at which resonance takes place -right
In H-NMR, what is special about alcohol? has broad peak from 1-5 ppm
In H-NMR, what is special about phenol? has broad peak from 4-7 ppm
In H-NMR, what is there is no adjacent hydrogens? singlet
In H-NMR, what is special about benzene? has peak around 7 ppm
In H-NMR, When you see a triplet and quartet in a 3:2 ratio, what does that indicate? H3C-CH2-
In H-NMR, when you see a doublet and a septet in a 6:1 ratio, what is it? isopropyl group [(H3C)2CH-]
What is the suffix for an ester? -oate
What is the pascal's triangle ratio for a triplet? 1:2:1
What is the pascal's ratio for a quartet? 1:3:3:1
What is pascal's ratio for a quintet? 1:4:6:4:1
A doublet of a doublet is indicative or ortho,meta, para? para
What does it mean to be aprotic? no hydrogens bonded to F, O, N
Is there a problem when protic / aprotic solvents are dissolved in D2O? protic --> undergo exchange
What type of solvent used for H-NMR? one with NO hydrogens
On a fischer projection, what happens when you interconvert 2 substituents? change chirality of stereogenic center
On a Fischer projection, what happens when you interconvert 3 substituents? nothing
How do diastereomers compare in their physical properties? Have different physical properties including MP, BP, and density
How many chiral centers are in a meso compound and in what orientation? even number / opposite chirality
What is the net optical rotation of a meso compound? 0 degrees --> optically inactive
The reflection of a meso compound can be classified as? reflects identical and original compound
When 2 enantiomers are they formed in equal or unequal quantity? DIastereomers? -equal quantity -unequal --> major and minor product
How can enantiomers be formed in an unequal ratio? chiral catalyst is present to create enantiomeric excess
Syn addition means? symmetric addition (both wedges or both dashes)
Anti addition means? unsymmetric addition (wedge and dash)
Do enantiomers rotate light? NO
Equation for enantiomeric excess % = measured specific rotation / specific rotation of pure enantiomer * 100%
What creates a good leaving group? stable base --> weaker base --> more acidic
Can diastereomers ever produce racemic mixture? NO
What defines a favorable nucleophilic substitution? forms a stronger bond than one is broken
What type of electrophiles are used for SN2? primary, secondary, tertiary
What type of nucleophile is favored with SN2? good nucleophile
What type of solvent is favored with SN2? polar, aprotic solvent like ethers and ketones
What type of electrophiles are used for SN1? tertiary, secondary, primary
What type of solvent is favored with SN1? polar, protic solvent like alcohol
What type of nucleophile is favored with SN1? poor nucleophile
What is the SN1 rate? SN2 rate? rate = k[electrophile] rate = k[electrophile][nucleophile]
Why is it important to keep substitution reactions at low temperatures? prevents competing E2 reaction
Does SN2 or SN1 have an intermediate? SN1
Does SN2 or SN1 require a good nucleophile? SN2
What does catalyst do? stabilizes transition state complex and lowers Ea
How do enantiomers compare with physical properties? identical physical properties
Does a racemic mix have a higher or lower MP and density than either enantiomers? -greater -> think of two hands clasping --> stronger connection
Which is nonsuperimposable: enantiomers or diastereomers? NEITHER ARE
Are enantiomers or diastereomers mirror images? enantiomers
When do racemic mixes form vs. diastereomers? -racemic forms when there is no preexisting chirality -diastereomers form when one of the reagents has a chiral center at a non-reactive site
Aliphatic straight chain form of alkane
For alkanes, how does increasing molecular mass affect BP and MP? Branching? -increase -BP decreases
What type of free radicals are best for halogenation of alkanes? tertiary free radicals
During halogenation, what happens during propagation? goes from one free radical to another free radical
During halogenation, what happens during termination? two free radicals combine to no free radicals
During halogenation, what happens during initiation? goes from zero free radicals to two free radicals
Why are slower reactions more selective than faster ones? more time to select the best site for reacting
In halogenation, is chlorination or bromination faster? Which is more selective/ chlorination / bromination
In halogenation, is bromination or chlorination more reversible? bromination slower than chlorination --> reversible
As energy is added, are more or less stable products formed? less stable
When does rearrangement occur? with carbocations
Why are there minimal di-halogenated products in free radical halogenation? after first X added, weakest bond is C-X and not C-H --> easier to remove X than H
What are the characteristics for E2 reactions in terms of base, electrophile, and temperature? strong bulky base, hydrocarbon with leaving group, high temp
In what orientation must the leaving group be for E2 reactions? anti
What type of conditions are best for E1 reaction? acidic and high temperatures
Assign "acidic / basic" to E1 and E2. E1 = acidic E2 = basic
How can carbocations undergo rearrangement? alkyl or hydride shifts
During electrophilic addition, where is the positive charge situated after the pi bond attacks electrophile? most substituted carbon
What type of nu should be used for electrophlic addition? weak base otherwise it will deprotonate intermediate to regenerate alkene
What type of conditions are electrophilic additions carried out in? acidic conditions
What can a protic solvent do? form H-bonds and transfer protons
If there is no optical activity in the reactants, can there be in the products? NO
When 2 substituents add at the same time, syn / anti? Add at different times? syn / anti
Markovnikov addition in alkenes electrophile adds to less substituted carbon and nu adds to more substituted carbon
Anti-Markovnikov addition in alkenes electrophile adds to more substituted carbon and nu adds to less subst. carbon
Kinetic control refers to the more stable ____ while thermodynamic control refers to the more stable ______. intermediate / product
Thermodynamic control favors higher or lower temperature higher temperature
Lower energy intermediate leads to kinetic / thermodynamic product? HIgher energy intermediate? kinetic / thermodynamic
Boltzmann distribution law As temperature increases, higher energy levels become more populated to absorb energy increase --> more primary carbocations than at lower temp
Kinetic control favors what type of 1,2 or 1,4 addition to conjugated dienes? 1,2 addition --> monosubstituted alkene is least stable
Thermodynamic control favors what type of 1,2 or 1,4 addition to conjugated dienes? 1,4 addition --> disubstituted alkene is most stable
Does a meso compound have an enantiomer or diastereomer? only diastereomer
The diene is nu/e while the dieneophile is nu/e? nucleophilic / electrophilic
EDG benefit dienes or dienophiles? dienes
EWG benefit dienes or dienophiles? dienophiles
Cope rearrangement converts 1,5-diene into another 1,5 diene
Claisen rearrangement converts 1,5-diene into either an aldehyde or ketone
What are the building blocks of steroids? isoprene units
Are terpenes UV active? YES --> pi bonds
Differences in conjugation and pi bonds results in differences in? UV absorption
How does steam distillation protect integrity when distilling natural oils? allows oils to vaporize at a temperature lower than their BP
Do strong bases make good nucleophiles? NO --> chance for deprotonation
Does an alcohol or aldehyde receive higher priority? aldehyde --> most oxidized carbon receives highest priority
All ketones are associated with ketals / acetals. All aldehydes are associated with ketals / acetals. ketals / acetals
In basic conditions, ketones turn into hemiketal / ketal? aldehydes turn into? hemiketal / hemiacetal
In acidic conditions, ketones turn into hemiketal / ketal? ketal / acetal
How to form a ketal or acetal? react aldehyde/ketone with alcohol
Transesterification esters exchange alkoxy group in presence of alcohol and acid
How are acid anhydrides formed? condensation (dehydration) reaction between 2 COOH at elevated temperatures
When you add water to an acid anhydride, what is produced? 2 COOH
Addition of heat to 2 COOH yields? acid anhyride
How to reduce amides into amines? strong reducing agent like LiAlH4
Do amino acids contain amide bonds? NO
Where are amide bonds formed? peptide bonds in px, guanine, uracil
Rank reactivities of carbonyl with anhydride, halogen, ester, amide halogen, anhydride, ester, amide
What dictates the reactivity of the carbonyl? acidity of the conjugate acid of leaving group
With a bulky base, does the kinetic or thermodynamic product get formed? Small base? kinetic / thermodynamic
What happens during oxidation in terms of loss/gains of O and loss/gains of H? gain O / lose H
What happens during reduction in terms of loss/gains of O and loss/gains of H? lose O / gain H
What are the steps of oxidation for a primary alcohol? primary alcohol --> aldehyde --> COOH
What are the steps of oxidation for a secondary alcohol? secondary alcohol -->ketone
Can a tertiary alcohol get oxidized? NO
Oxidizing agents have lots of ____ while reducing agents have lots of _____. oxygens / hydrogens
What reagent allows oxidation from primary alcohol to aldehyde only? PCC
What does FADH2 reduce? hydrogenation of a pi bond
What does hydrazine (H2NNH2) reduce aldehydes and ketones to? alkanes
What does LiAlH4 reduce? COOH and Esters back to primary alcohols
What does NaBH4 reduce? aldehydes and ketones back to primary and secondary alcohol
What does a Gignard reaction produce? new carbon-carbon bond
The 4th step of glycolysis is what type of reaction? retro-aldol reaction with aldolase
Wittig Reaction converts a ketone into an alkene with a phosphorous ylide
Pinacol rearrangement converts a vicinal diol into a ketone
Iodoform Reaction Converts a methyl ketone into a COOH and a haloform -haloform = CX3
Wolff-Kishner Reduction uses hydrazine under basic conditions to reduce a ketone/aldehyde into an alkane C=O + NH2NH2 --> -CH2- + N2
Protecting groups turn aldehydes, ketones, and alcohols into? acetals, ketals, silyl ethers
Where do oxidations and reductions take place in the cell? -oxidations - mito matrix (glycolysis is exception) -reductions - cytoplasm
Is anabolism an oxidative or reductive process? Catabolism? Reductive / oxidative
Are NAD+ / FAD oxidizing or reducing agents? oxidizing agent
Rank boiling points of alcohols based on primary, secondary, tertiary. primary > secondary > tertiary
Water solubility is high for carbonyls with ___ carbons four
Alcohol + COOH = ? ester
Can a Grignard add twice to a carbonyl? YES if there is a leaving group
Difference between D vs. L D: H --OH L: OH --H
Difference between (+) and (-) All stereocenters are switched between the two
epimers diastereomers that differ around one chiral center
What type of sugar is fructose? ketohexose
When sugars are D and L, it also means that one has to be _ and the other _. + / -
Alpha/beta anomers, is alpha pointing up or down? Beta? What does it really mean in terms of cis/trans? alpha-down (trans with last carbon) beta-up (cis with last carbon)
Mutarotation conversion between anomers
Is the alpha or beta anomer more favored in vivo? beta
Going from dashes/wedges to Fischer, dashes are on the right/left? right
Going from dashes/wedges to Fischer, wedges are on the right/left? left
Ketose-aldose as well as glucose isomerization proceeds through what type of intermediate? enediol intermediate
How many carbons does glyceraldehyde have? 3
The sugars in amylose and glycogen have what type of linkages? Cellulose? alpha / beta
Branching is created from what type of linkages? 1,6
Which polysaccharides have branching? Which do not? -Amylopectin and glycogen have branching -cellulose and amylose do not have branching
Natural sugars have what type of chirality? D
What does nitric acid sugar oxidation test for? optical activity
How does osazone test work? phenylhydrazine is used to form an osazone --> C2 epimers ield the same osazone
What does Tollen's test test for? tests for distinguishing between aldehyde and ketone --> aldehyde are readily oxidized while ketones are not
What are reducing sugars? hemiacetal or aldose
For Tollen's test, if a silver mirror forms, what doe sthat mean? presence of an aldose
What does the periodate test (IO4-) do? oxidizes sugar by cleaving all C-C bonds
What does Kiliana-Fischer synthesis do? adds new carbon through cyano group that is converted to an aldehyde --> creates 2 epimers not in 50/50 ratio
Addition of cyanide is involved with which process? Kiliani-Fischer synthesis
Ruff degradation (and Wohl degradation) decreases chain length by one carbon when CO2 leaves (1st carbon) --> bromine in water
What reagent does nitric acid sugar oxidation use? HNO3
What reagent does Kiliani Fischer synthesis use? KCN and H2/Pd
What reagent does Ruff degradation use? Br2 and H2O
What is the difference between Type O and Type A/B in terms of glycoproteins? Type O has 3 sugars (one is L) while Type A/B has 4 sugars
How can you tell the number of valence electrons? look at group number --> different from oxidation number
amide O=C-NH2
Imine C=N-R
Hydrazone C=N-NH2
Nitro O=N-O
Diazo C=N=N
Azide N=N=N
Sulfate vs. sulfite 4 oxygens vs. 3 oxygens
syn periplanar eclipse bulky groups eclipse each other
anticlinal eclipsed bulky groups eclipse hydrogen
polarized left rotation - / l
polarized right rotation + / d
Separate enantiomers? Convert E --> D, separate D, convert back to E
What does UV absorption show? molecular orbital transitions from bonding to antibonding orbitals results in UV absorption
Why do double bonds absorb UV? pi electrons transition from bonding and nonbonding molecular orbitals to antibonding orbitals
What is mass spectroscopy? bombard a molecule with electrons and it fragments into ions
What does mass spectroscopy NOT detect? uncharged molecules
What is a neighboring hydrogen in NMR? 3 bonds away
In extraction, what 2 phases are there? organic and aqueous phase
In extraction, what does the organic phase solvent consist of? nonpolar solvent like oil, chloroform
Basic premise behind chromatography? stuff that sticks to stationary phase will come out slower
What is recrystallization? barely dissolving cpd and letting it recrystallize out of solution (more pure)
What type of solvent for recrystallization? solvent in which cpd is soluble at warm temp but not at cool temp --> impurities are highly soluble
What alkane has the same BP as water? heptane
What is the best protecting groupfor alcohols? Cl-Si-Me3 --> deprotect with F-
R-OH + SOCl2 --> ? R - Cl -SO2 + HCl
R-OH + PBr3 --> R - Br -H3PO3, R3PO3, HBr
What are the use of mesylates and tosylates? transform -OH into a good leaving group by reacting with MsCl or TsCl
Toluene Ph - CH3
What creates an ester? carboxylic acid + alcohol
How to create an inorganic ester? replace carbon of esters with different atoms (like P or S)
What is a phosphodiester linkage? 3'-OH attacks 5'-phosphate
Rank BP: COOH, ketones, alcohol COOH > OH > ketones
How many equivalents of alcohols do aldehydes/ketones react with to make hemiacetals? 1
How many equivalents of alcohols do aldehydes/ketones react with to make acetals? 2
primary amine + aldehyde/ketone =? imine: -N=C
secondary amine + aldehyde/ketone =? enamine -N-C=C |
What happens during a haloform reaction? methyl ketone reacts with Cl, Br, or I in the presence of hydroxide ions to give a carboxylate and a haloform --> halogenates at alpha position
What is a haloform? alkyl halide with 3 X substituents
What is the iodoform test? the use of haloform reaction to identify methyl ketones because iodoform is a yellow solid
Can aldehydes undergo the haloform reaction? ONLY acetylaldehyde
Is the haloform a good or bad leaving group? good L.G.
What do 1,3-dicarbonyls create? internal H-bonding from tautomerism -H-bond btwn carbonyl and alcohol
Is the keto or enol form more stable? keto --> predominant form
Do EWG or EDG make an alpha proton more acidic? EWG
Do COOH's act both as nucleophiles and electrophiles? YES -electrophilic carbonyl and nucleophilic -OH
What is a beta-keto acid? carboxylic acid with a ketone group in beta position from carboxylic acid
For what type of acids does decarboxylation occur? beta-keto acid
Steps to halogenation of COOH at alpha position ONLY. -COOH --> acyl halide -enolize -alpha attacks electrophile -revert back to COOH
Generally, is COOH a strong or weak acid? weak acid
What is the pKa of H+? 0
What creates a good acid no matter what? resonant stability of conjugate base
Suffix for anhydrides -oic anhydride
What is the IR-spectrum for acid chloride? around 1800 cm-1
What is the IR-spectrum for anhydride? 2 bands between 1700 and 1800 cm-1
What is the IR-spectrum for amide? -NH at 3300 cm-1 -C=O at 1700 cm-1
What is the IR-spectrum for an ester? -C=O at 1700 cm-1 -C-O at 1200 cm-1
COOH + SOCl2 --> acid chloride
COOH + COOH + heat --> anhydride
acid chloride + COOH + base --> anhydride
acid chloride + alcohol + base --> ester
acid chloride + amine --> amide
acid chloride + water --> COOH
Are COOH more or less stable than aldehydes and ketones and why? more stable --> resonance
What is the reactivity of carboxylic acid derivatives? anhydride, ester, Cl, amide Cl > anhydride > ester > amide
What does Hofmann Rearrangement do? takes away the C=O of an amide
How to cause decarboxylation? beta-keto COOH are heated
What is the leaving group for the hydrolysis of amides? neutral amine
Can amide bonds rotate? NO --> partial double bond characteristic between C-N
What is a beta-lactam? Does it have high or low ring strain? 4-membered cyclic amide --> high ring strain
Why do beta-lactams have higher ring strain? can't rotate to achieve more stable configuration
How to synthesize acetoacetic ester, a beta-keto ester? Claisen condensation of 2 ethylacetates
Why can beta-keto acids undergo decarboxylation? beta-keto group stabilizes resulting carbanion via enol formation
What is acetoacetic ester synthesis used for? acetoacetic ester is used to synthesize a new ketone -->alpha acidic proton, attack new R group, decarboxylation
How to turn acid chloride, anhyride, ester, and amides back to COOH? add water
Are tertiary amines chiral / racemic? Chiral --> racemic (spontaneous inversions)
Are quarternary amines chiral / racemic? chiral and stay chiral
What is the IR-spectrum for primary amines? 2 peaks around 3300 cm-1
amine + acid derivative with good L.G. --> amide
What is the reaction between a primary amine and nitrous acid? -NH2 + HONO --> -N2+
Can the amine group be alkylated? YES
Hoffman Elimination amine + methyl iodide --> exhaustive methylation of amine --> elimination with methylated amine as leaving group
Does Hoffman Elimination form more or less substituted double bond? less
Zaitsev vs. Hofman Zaitsev - more substituted Hofman - less substituted
Zaitsev vs. Hofman: E1 vs. E2 forms which? -E1 = Zaitsev -E2 with bulky base = Hofman
Think about BL base-do bases like to gain or lose protons? gain protons
Are protons lost easier in amines or amides? amides --> resonance
Are aromatic amines weaker or stronger bases than aliphatic amines? weaker bases --> donates electron density to aromatic ring
Ortho effect introduce any bulky substituent at the ortho position to another substituent -due to steric repulsions, planarity of ring is lost, resonance reduced --> more acidic
What will give a positive Tollen's Reagent test? any sugar in hemi acetal form --> acetal sugars are nonreducing
How to tell if reducing / non-reducing? look for available anomeric carbon -available - hemiacetal -not available - acetal
Typically, how to generalize reducing vs. nonreducing? reducing = aldoses, ketoses nonreducing = surcrose and disaccharides
Hemiacetal vs. acetal -hemiacetal - alcohol and ether on same carbon -acetal - 2 ethers on same carbon
Created by: 507935299 on 2012-07-03



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